用分部积分法求积分，这道题要用两次分部积分。有答案，求过程。 用分部积分法求这两道题 求具体过程～谢谢
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\u5982\u56fe
=-sin(lnx)/x|(1,e^(π/2))+∫(1,e^(π/2)) cos(lnx)/x^2dx
=-1/e^(π/2)-∫(1,e^(π/2)) cos(lnx)d(1/x)
=-1/e^(π/2)-cos(lnx)/x|(1,e^(π/2))-∫(1,e^(π/2)) sin(lnx)/x^2dx
=-1/e^(π/2)+1-∫(1,e^(π/2)) sin(lnx)/x^2dx
所以原式=[1-e^(-π/2)]/2
绛旓細鎵浠ュ師寮=[1-e^(-蟺/2)]/2
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